DENVER — Dignitaries from three nations sniffed marijuana, walked through greenhouses full of tagged marijuana plants and learned about video pot surveillance on a three-day Weed 101 tour in Colorado, which has a regulated marijuana market and is planning to expand sales to all adults in a few...

DENVER — Dignitaries from three nations sniffed marijuana, walked through greenhouses full of tagged marijuana plants and learned about video pot surveillance on a three-day Weed 101 tour in Colorado, which has a regulated marijuana market and is planning to expand sales to all adults in a few weeks.

More than two dozen visiting officials from Canada, Mexico and Uruguay made the trip this week. Colorado is preparing to play host for 1,000 drug policy experts and legalization backers at the International Drug Policy Reform Conference.

"We see the hypocrisy of the American policy toward Latin America," said Julio Calzada, drug czar in Uruguay, which is expected to become the first country in the world to license and enforce rules for the production, distribution and sale of marijuana for adult consumers.

"We have thousands of deaths, simply a product of prohibition. And here you have a very regulated market, marijuana that is produced in a controlled fashion. That is where we are going."

Calzada and the other dignitaries toured marijuana dispensaries and growing sites. They also huddled with Colorado officials to learn about how the drug is taxed and sold.

Marijuana legalization will be a major topic at the conference. Colorado and Washington state have authorized pot possession for all adults over 21, with retail sales beginning next year. Conference attendees are all interested in rethinking drug policy, if not legalizing pot outright. The dignitaries scribbled in notebooks, took pictures with their phones and huddled with interpreters to learn the nuances of the legal drug market in the U.S.

Visitors from Mexico, where nationwide legalization isn't under serious consideration, said their country is watching closely to see how Colorado and Washington policies play out.

"I think we need to see this as an opportunity," said Fernando Belaunzaran, a Mexico City congressman who supports marijuana legalization.

"We've had 100 years of prohibitionist policies, and no one has paid a higher price" than Mexico, Belaunzaran said.

The tour also attracted two pro-legalization members of the Canadian Parliament.

"Colorado has put together a pretty impressive regulatory scheme," said Sen. Larry Campbell of Vancouver.

The visitors all gaped at the numbers of cameras they saw in Colorado dispensaries, along with the computer tracking accessed with biometric authentication, a fingerprint held to a computer.

The owner of one of the dispensaries on the tour, Norton Arbalaez, boasted that his dispensary tracks plants "the same way Wal-Mart does tracking."

The whole thing got a laugh from Camilo Collazo, a legalization advocate from Mexico.

"It was amazing, how American all this was," Collazo said with a laugh after the tour. "It's all dignified, very American, business efficiency first."

Collazo expects other countries will interpret marijuana regulation differently, but still be inspired by change in the U.S.

"The United States has no longer legitimacy to enforce the law abroad without enforcing it here. So I think politicians worldwide are more open to looking at this, too."

Public polls in the U.S. show mounting support for legalizing the drug. A nationwide Gallup poll released this week showed 58 percent think pot should be legal. The poll surveyed 1,028 people by phone Oct. 3-6

When Gallup first asked the question in 1969, only 12 percent favored legalization.